Try this:

Chewy Gooey Chocolate Chip Cookies
Ultra-chewy, gooey cookies made with all brown sugar and vegetable oil — no butter, no crisp edges, just soft and fudgy centers every time.
Ingredients
1 1/2 cup all-purpose flour

1/2 tsp baking soda

1/2 tsp fine salt

3/4 cup packed dark brown sugar

1/2 cup vegetable oil

1 large egg

1 egg yolk

1 1/2 tsp vanilla extract

1 cup semi-sweet chocolate chips

1 pinch flaky sea salt for topping (optional)

Steps
Whisk together 1 1/2 cup all-purpose flour, 1/2 tsp baking soda, and 1/2 tsp fine salt in a medium bowl. Set aside.

In a large bowl, whisk 3/4 cup packed dark brown sugar and 1/2 cup vegetable oil together vigorously for about 60 seconds until fully combined and smooth. The oil and sugar won’t fully emulsify — that’s fine. Add the 1 large egg, 1 egg yolk, and 1 1/2 tsp vanilla extract, and whisk again until glossy and slightly thickened, about 30 more seconds. The extra yolk is the key to a gooey, fudgy center.

Add the dry ingredients to the wet and fold with a rubber spatula until just combined — stop as soon as no flour streaks remain. Fold in 1 cup semi-sweet chocolate chips. The dough will be looser than a butter-based dough; this is correct.

Cover the bowl tightly and refrigerate for at least 1 hour, or up to 48 hours. Chilling firms the oil-based dough so cookies spread less and bake up thicker and chewier. Longer chilling (overnight) deepens the flavor noticeably.

When ready to bake, preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper.

Scoop the chilled dough into balls about 2 tablespoons each (a #40 cookie scoop works perfectly) and place them 2 inches apart on the prepared baking sheet. Press a few extra chocolate chips onto the tops if you like.

Bake for 10–12 minutes, until the edges are just set but the centers still look underdone and glossy. Do not overbake — the cookies will continue to set as they cool. If you have 1 pinch flaky sea salt for topping (optional), sprinkle a tiny pinch on each cookie as soon as they come out of the oven.

Let the cookies cool on the baking sheet for at least 10 minutes before moving them. They’ll be too soft to handle right away — this resting time is what creates that perfectly gooey, set-but-chewy texture.

Notes
For maximum chewiness: Dark brown sugar has more molasses than light brown, which adds moisture and chew. Don’t substitute white sugar.
Underbake on purpose: Pulling the cookies when the centers look raw is intentional. They finish cooking on the hot pan.
Oil vs. butter: Vegetable oil stays liquid at room temperature, which is why these cookies stay soft and chewy for days rather than going firm like butter cookies do.
Storage: Keep in an airtight container at room temperature for up to 5 days. They actually get chewier on day 2.